1. Field of the Invention
One of the basic pollution problems that concern us today is that of sewage and solid waste disposal and treatment, as well as the management of the organic by-products derived therefrom. It has been determined through extensive research that the biological treatment of organic-containing municipal, domestic and industrial waste materials, including also agricultural wastes, animal wastes and other organic debris, offers the best practicable approach to dealing with these problems. In general, conventional biological processing systems for the treatment of organic-containing waste materials rely upon microorganisms to absorb and metabolize the organic components of the incoming wastes. The microorganisms are typically introduced into such systems and contacted with the influent by means of return or "re-cycled" sludge, which contains these microorganisms although the microorganisms may also be introduced otherwise or may even be allowed to grow and reproduce naturally. The functional portion of all biological systems is directly related to the number and physiological state of the microorganisms which are present within the system.
Accordingly, of the various methods for the treatment of sewage and other organic-containing waste matter currently known or contemplated as technically and ecologically feasible, the one thing that all such treatment methods have in common is a biological treatment or biodegradation step employing the use of bacteria which simulate the biological degradation process which normally takes place in nature. It is the purpose of such a biological treatment or biodegradation step to convert the organic matter contained in the influent waste matter so as to yield a new stabilized bacterial biomass matter which is commonly known as sludge (although most typically, a "sludge" refers to the biomass resulting from the treatment of human waste, while "humus" is used to identify the resulting product of agricultural wastes). Thus, while the various known biological treatment processes may differ in the extent to which the organic-containing waste matter is pre-treated, i.e., in order to remove solid matter, grit matter, suspended solids and the application of other so-called primary-treatment methods, or the extent and conditions under which the biological or biodegradation treatment takes place, i.e., the so-called secondary-treatment methods, whether activated sludge is used or not, or the extent and conditions under which the resulting effluent is further treated or improved, i.e., by chemical addition and other so-called tertiary treatment steps, or the extent and conditions under which the resulting sludge is further treated or improved, all such processes rely upon the biological action of bacterial microorganisms upon the organics contained in influent matter. As noted, such biological action may itself vary in respect to the condition under which the biological action is allowed to take place, for instance, whether under aerobic conditions, or anaerobic conditions, or faculative processing, each condition favoring specific forms of bacterial microorganisms, with the aerobic processes depending upon the presence of aerobic bacterial which require free oxygen for their metabolism while anaerobic processes foster bacteria which do not require free oxygen, but instead, derive their oxygen from the availability and presence of substance such as sulfates, phosphates and various organic compounds.
A yet further area in which biological action is relied upon is in the composting of solid organic-containing waste matter wherein the organic waste matter is biologically acted upon by bacterial microorganisms so as to likewise decompose and convert the organic matter in order to yield a stabilized sludge or humus material. As in the case for the biological treatment of liquid sewage and other organic-containing waste matter, the biological action in composting processes may also be carried out under aerobic or anaerobic conditions.
Another feature that all methods for the treatment of organic-containing waste material by means of a biological treatment or degradation step have in common is a requirement that the biological process be carried out to such an extent and for a length of time sufficient to "destroy" or "neutralize" the deleterious organic matter contained in the waste material and especially the harmful, i.e. pathogenic microorganisms such as bacteria, viruses and protozoa, as well as to reduce the odor, the volatile organics, etc., so as to thereby yield a relatively benign bacterial-containing matter product commonly referred to as sludge. It should be noted, however, that activated sludge processing for the production of fertilizer generally does not allow for complete digestion and stabilization of organic material. To this end, it is readily apparent that the biological treatment step of any conventional waste treatment system must be so designed so as to ensure that the biological degradation process is allowed to progress for a sufficient time before such action is caused to be terminated. While various methods have been suggested for "speeding-up" or "intensifying" the natural biological action, most such methods rely upon some sort of a chemical additive and none of such methods have proven satisfactory. The relatively long residence time necessary in order to achieve the desired bacterial degradation and the desired resulting sludge material remains today one of the major features of all biological waste treatment systems which makes these systems uneconomical.
Closely associated with the ecological problems relating to the treatment of liquid and solid organic-containing waste matter by means of biological action to produce a sludge is the further problem of what is to be done with the vast amounts of sludge produced by these various processes. Today, several alternative sludge management practices are contemplated including but not limited to ocean disposal--no longer viable because of ever-increasing regulatory limitations--incineration, landfill, fertilizer and soil reclamation applications; "Municipal Sludge Management: Environmental Factors", Publication MCD-28, October 1977; "Sludge Handling and Disposal Practices At Selected Municipal Wastewater Treatment Plants", EPA Publication MCD-36, April 1977. Of all of the foregoing, fertilizer and soil reclamation applications for sewage and other waste matter sludge has been of greatest interest. However, due to the relatively low nutrient value of traditional sewage sludge--low as compared to commercial fertilizers and other soil additives, particularly in respect to the total nitrogen, phosphorous and potassium content--such fertilizer and soil reclamation applications have not gained wide acceptance. For instance, sludges typically contain only from 1-6% total nitrogen by weight and only from 1-3% by weight, phosphorous, "Application of Sewage Sludge to Croplant", EPA No. 430/9-76-013, Publication MCD-33, Nov. 1976, at pages 16 and 18, and more typically about 3% nitrogen, 2.5% phosphorous and 0.3% potassium, "Municipal Sludge Management: EPA Construction Grants Program", EPA Publication MCD-30, April 1976, at page 9. This has severly limited the feasibility of using sludges for fertilizer and soil applications.
As such, it can be seen that all conventional organic-containing waste treatment processes employing a biological treatment or degradation step have at least two disadvantageous features in common, viz, a relatively long requisite period during which the biological action must be allowed to take place and a relatively low nutrient value for the resulting sludge product. It is primarily in respect to these disadvantageous features of the state of the art that the present invention is directed, although further significant beneficial features of the instant invention, as discussed herein, also will be realized.
As noted above, the microorganisms which are required to initiate biological degradation are typically supplied to the waste system's biological treatment step by return or "recycled" sludge which contains these microorganisms. This sludge may or may not also represent the product resulting from the biological treatment step of the waste treatment process and, as noted, it may or may not be further processed or treated prior to its removal from the waste treatment system. The effectiveness of the sludge, whether for its action upon influent raw organic-containing waste matter in supplying the initial number of microorganisms, or for its fertilizing and/or soil additive properties owing to its inherent nutrient value, is directly related to the number and physiological state of the "living cells" that are present in the sludge and which absorb and metabolize the organic components of the influent waste matter. These living cells are the functional portion not only of the sludge but also of the entire waste treatment process. It is now generally accepted that because the chemical "adenosine triphosphate" (ATP) is universally present in all living microorganisms, that its measurement will yield a fast and an accurate indication of the relative effectiveness of the sludge. Measurement of the ATP value of sludge is also known as "biomass" determination and is more fully discussed is "Biomass Determination--A New Technique For Activate Sludge Control", Water Pollution Control Research Series, PB 211 127, Jan. l972.
2. Description of the Prior Art
Various additives to the biological treatment step, to the raw waste material, and/or to the resulting sludge have been proposed so as to enhance the properties of the sludge. Thus, for instance, Goordman et al U.S. Pat. No. 3,892,553 discloses the addition of mine tailings to waste matter to produce a synthetic top soil. The minerals involved are not specific in their analysis and are used for their physcial properties in the formation of a soil matrix. The minerals recommended for use are "spent" by-products of the mineral processing industry and possess a relatively very low nutrient value. The end product is a high mineral to organics ratio soil. This patent also refers to sewage as an alternative additive ingredient in the recited invention; however, sewage sludge is an end product of conventional biological waste treatment processing and is an area with which the patent is not concerned.
Lawton U.S. Pat. No. 1,029,378 concerns itself with rendering minerals available through long term aerobic fermentation, and generally attempts to improve upon processes used by commercial chemical firms for isolating fertilizer elements. The Lawton patent does not apply the invention to biological processing of sewage influent by current biological processing nor does the patent use a specific mineral analysis and the disclosure of this patent does not provide for microbial stimulation over and above the natural processing rate.
Eweson U.S. Pat. No. 3,235,369 deals with the production of a granulated fertilizer and the patent does not specify any particular mineral analysis. The primary objective of this patent is to simplify product handling and physical disposal. The silica minerals of the patent, preferably ground glass, are used for the purpose of granulating agents and are not disclosed as capable of stimulating microbial populations significantly over natural processing. This patent does mention various minerals as food sources for microbes but only for their adhering qualitites and not as a broad based microbial stimulant. Generally, the process of the patent is dependent on the natural intensity of microbial activity and does not at all deal with intensifying natural microbial activity.
Wallace et al U.S. Pat. No. 1,260,103 concerns itself with adding organic and inorganic materials to garbage and refuse for the sole purpose of absorbing liquid and "toxic" by-products of microbial development. The patent does not mention that the mineral addition increases the microbial population significantly over the natural course of processing.
Earp-Thomas U.S. Pat. No. 1,938,647 describes a process wherein bacterial strains and culture mediums are added to organic wastes and composted. The patent does not claim a broad based biological increase but rather attempts to introduce a specific bacteria that is already naturally indiginous to the process in the hopes that it will predominate. The minerals and fertilizing elements that the patent adds are at the end of the digestion process and are a secondary supplement prior to fertilizer distribution.